Enable MIT SHM and implement scrolling in the window surface

Stealing a bit from the Qt X11 source code...

2 files changed, 64 insertions, 9 deletions

diff --git a/src/plugins/graphicssystems/testlite/qwindowsurface_testlite.cpp b/src/plugins/graphicssystems/testlite/qwindowsurface_testlite.cpp
index c0a0cc9..0afbf2f 100644
--- a/src/plugins/graphicssystems/testlite/qwindowsurface_testlite.cpp
+++ b/src/plugins/graphicssystems/testlite/qwindowsurface_testlite.cpp
@@ -114,11 +114,68 @@ void QTestLiteWindowSurface::setGeometry(const QRect &rect)
     xw->setGeometry(rect.x(), rect.y(), rect.width(), rect.height());
 }
 
+//### scroll logic copied from QRasterWindowSurface, we should make better API for this
+
+void copied_qt_scrollRectInImage(QImage &img, const QRect &rect, const QPoint &offset)
+{
+    // make sure we don't detach
+    uchar *mem = const_cast<uchar*>(const_cast<const QImage &>(img).bits());
+
+    int lineskip = img.bytesPerLine();
+    int depth = img.depth() >> 3;
+
+    const QRect imageRect(0, 0, img.width(), img.height());
+    const QRect r = rect & imageRect & imageRect.translated(-offset);
+    const QPoint p = rect.topLeft() + offset;
+
+    if (r.isEmpty())
+        return;
+
+    const uchar *src;
+    uchar *dest;
+
+    if (r.top() < p.y()) {
+        src = mem + r.bottom() * lineskip + r.left() * depth;
+        dest = mem + (p.y() + r.height() - 1) * lineskip + p.x() * depth;
+        lineskip = -lineskip;
+    } else {
+        src = mem + r.top() * lineskip + r.left() * depth;
+        dest = mem + p.y() * lineskip + p.x() * depth;
+    }
+
+    const int w = r.width();
+    int h = r.height();
+    const int bytes = w * depth;
+
+    // overlapping segments?
+    if (offset.y() == 0 && qAbs(offset.x()) < w) {
+        do {
+            ::memmove(dest, src, bytes);
+            dest += lineskip;
+            src += lineskip;
+        } while (--h);
+    } else {
+        do {
+            ::memcpy(dest, src, bytes);
+            dest += lineskip;
+            src += lineskip;
+        } while (--h);
+    }
+}
+
 bool QTestLiteWindowSurface::scroll(const QRegion &area, int dx, int dy)
 {
-    return QWindowSurface::scroll(area, dx, dy);
+    if (!xw->image() || xw->image()->isNull())
+        return false;
+
+    const QVector<QRect> rects = area.rects();
+    for (int i = 0; i < rects.size(); ++i)
+        copied_qt_scrollRectInImage(*xw->image(), rects.at(i), QPoint(dx, dy));
+
+    return true;
 }
 
+
 void QTestLiteWindowSurface::beginPaint(const QRegion &region)
 {
     Q_UNUSED(region);
diff --git a/src/plugins/graphicssystems/testlite/x11util.cpp b/src/plugins/graphicssystems/testlite/x11util.cpp
index f3b6dc2..de2a6d9 100644
--- a/src/plugins/graphicssystems/testlite/x11util.cpp
+++ b/src/plugins/graphicssystems/testlite/x11util.cpp
@@ -73,9 +73,7 @@
 
 //#define MYX11_DEBUG
 
-//MIT SHM disabled by default, since we haven't implemented ShmCompletion synchronization yet
-
-#define DONT_USE_MIT_SHM
+//#define DONT_USE_MIT_SHM
 
 static int (*original_x_errhandler)(Display *dpy, XErrorEvent *);
 static bool seen_badwindow;
@@ -506,14 +504,14 @@ void MyWindow::paintEvent()
         //qDebug() << "Here we go" << image_info->image->width << image_info->image->height;
         int x = 0;
         int y = 0;
-        // We should really set send_event to true, and then use the XShmCompletionEvent
-        // to synchronize painting
+
+        // We could set send_event to true, and then use the ShmCompletion to synchronize,
+        // but let's do like Qt/11 and just use XSync
         XShmPutImage (xd->display, window, gc, image_info->image, 0, 0,
                       x, y, image_info->image->width, image_info->image->height,
-                      /*send_event*/ false);
+                      /*send_event*/ False);
 
-        //### This makes output visible, probably not ideal from a performance point of view...
-        XFlush(xd->display);
+        XSync(xd->display, False);
     }
 #endif
 }